There are basically two different MiniDisc formats. The classic MiniDisc (MD) is a 160MB disc that uses ATRAC (adaptive transform acoustic coding) to compress different portions of the audio spectrum differently to different degrees. It's a lossy compression format (sort of a precursor to MP3, at least in very broad terms). There's also a very new Hi-MD format that increases disc capacity to 305MB (re-formatted standard MD) and 1GB (new media with MD form factor). The 1GB Hi-MD discs seem to run around $7 each, and the regular MD's can be had for a little over a dollar if you buy packs. Hi-MD supports lossless (PCM) storage and USB connection to PC's for data transfer to a computer. This would probably be the better format for preserving the best audio quality (94 minutes of PCM data, essentially the same data as a CD).